Unsolved Mysteries of Physics

In My Humble Opinion
1

Ok, I have a friend coming to stay with me soon, and he asked me to do him a favour: To think about what the great unsolved mysteries of physics are, and discuss them with him when he arrived.

My face: :eek:

The problem is that my physics is kinda rusty at the moment. The last year of physics has been mindnumbingly slow, so I’ve been focusing more on maths (double :eek: - I’m turning into a mathematician!), so my mind is drawing something of a blank here.

So far I’ve come up with:

Unification of quantum mechanics and general relativity, or at least a quantum theory of gravity.

Do the 4 fundamental forces unify at high energies? Some theories predict they do, but those don’t have much in the way of experimental verification (e.g. Supersymmetry). I’m not sure if this one is still true or not.

Does Dark Matter exist or have we got a failure in our understanding of gravity? If it exists, what is it?

Is there anything to string theory, M-theory, etc, or are they just really neat?

What the hell happens to all those disappearing socks? :slight_smile:

While we’re at it, can anyone reccomend some good, reasonably general, books/papers on physics? Popular science or textbooks are equally ok - I can handle the maths (a significant amount of it anyway, and I can try and teach myself the rest).

Thanks in advance

2

Is gravitational mass the same as inertial mass?

3

I thought that had been verified to an insane degree of accuracy and it was pretty much taken for granted that the answer was yes?

4

Yes, that’s been verified pretty well, I think, by several independent types of experiment. Try doing a search for Eotvos, which I believe should be of help.

Other unsolved mysteries… Hmm…

QCD: right or not? It looks good, but is unfortunately fairly difficult to calculate with at times because of the strength of the coupling constant.

Inflation: a neat story, with several different models… are any right?

Where in the heck is the Higgs boson?

5

How about:

  • Is time travel possible? According to Relativity it is but for most of us the consequences are too weird to accept that easily.
    On the lighter side:

  • Perpetual Motion: Would a giant buttered toast/cat array actually work?

  • How do Bumble Bees manage to fly (I once heard that it was thought they should be aerodynamically incapable of flight).

  • Isn’t there a pitch in baseball that confounds physicists as to how the ball does what it does?

6

Some more stuff:

  • Gravastars vs. Black Holes

  • Do Strange Stars (or Quark Star) exist as a possible step between a Neutron Star and a Black Hole (or Gravastar)?

7

11 Physics Questions for the New Century.

8

Behold, the mysteries/myths of bumble flight are discussed by Cecil here.

9

This was explained years ago under the Quantum Theory of Hosiery; as soon as enough lint builds up in the trap, one sock disappears.

10

And further elucidated in this thread

11

I thought the gravastar/black hole debate had been resolved? I don’t remember the details, but someone observed an object that was massive enough that it had to either be a gravastar or a black hole, and the way the surrounding matter radiated (or possibly didn’t radiate?) showed it had to have an event horizon. I think I read the article in new scientist.

Or am I going crazy?

12

I’m not sure that it’s been resolved or not, but it may well be. Try doing a board search here on them; I know Chronos had some comments about them and was pretty skeptical.

An additional mystery: we understand, we think, how particles gain mass, but I don’t know that anyone is making any claims to being able to “predict” the mass of various elementary particles. Why are the masses what they are?

13

Here. This is the article I was thinking of.

14

I was given a book called “The Physics of Baseball” for my birthday once. My friend probably leaped on it immediately when he saw it, thinking of me on both counts.

The point here is that I think the pitch mentioned above that has baffled physicists, supposedly, is the curve ball. The batters have reported for decades that the ball curves at the last, but the scientists have said that there’s no way the effect of the spinning threads just kicks violently into gear halfway to the plate.

The physicists are correct. There is a pretty much constant curve in the path of a good curveball. The book I mentioned showed a strobe photo of a curveball, with a background of height-marked poles, to measure the height of the ball.

The ball is thrown slightly up, but immediately starts on its curve, helped of course a little by gravity. The batter sees the ball as moving very little vertically as it goes up a bit, then down that same amount. This of course takes time, and the ball may be about halfway to the batter. As the curving continues, the ball “drops off the table”, and often completely surprises the batter.

15

Are the laws of physics absolutely constant through time and space?

There is some indication that the fine constant has altered slightly since the start of the earth.